Vehicle Lightweighting: Materials, Processes and
Life Cycle Assessment
LCVTP – Final Dissemination Event
21st February 2012
Geraint Williams, WMG
Workstream Partners: Ricardo, WMG, MIRA, Coventry University, TMETC, Jaguar Land Rover
Associate Partner: Alpha Adhesives
LCVTP: Work Stream 7
• Objective:
>
To develop materials and process technologies that will facilitate the
introduction of lightweight solutions into future electric / hybrid vehicle
programmes without compromising the overall life cycle impact.
Challenges and Considerations
•
Product application
> Structural performance and generation of CAE models
> Durability
•
Manufacturing implications
> Formability and joining
> Volume manufacture and introduction into existing facilities
•
Environmental impact
> Impact of alternative material on Life Cycle CO2
> LCA methodologies
WS 7 - Key Tasks and Deliverables
• BIW Material Technologies
Determine suitability of candidate materials and process combinations
to minimise the weight of structural automotive applications.
Provide robust design and process guidelines for the best assembly
and joining methods for a given set of material / joint interfaces .
• Lightweight seat construction
Identify and evaluate materials and process options for lightweight
seat structure concepts.
• Lightweight EV architecture
Understand the complexities and develop a scalable architecture
Deliverables
• Reports on current and emerging
technologies
• Generic part and design data
• Validated concepts
model that can be applied to EV, REEV and Series Hybrid vehicles.
• Lightweight glazing
• Design and application proposals
Identify a lightweight glazing solution for each vehicle application that
• Design and process guidelines
optimises the optical, acoustic and thermal transmission performance.
• Roadmap to future opportunities
• Life Cycle Analysis
Ensure that materials and process technologies identified are evaluated
for their environmental performance to minimise any adverse impact.
• LCA indicator
Key Achievements
•
Test methodology for composites developed and correlation with computer
simulations established
•
Viable medium/high volume composites manufacturing process for structural
applications demonstrated
•
BIW structural component weight saving of at least 20%
•
Projected front seat weight saving of over 33%
•
Lightweight glazing technology opportunity identified
•
Rapid life cycle calculator developed and life cycle CO2 footprint of LCVTP
vehicle established
•
Dissemination events included technology reviews (3), workshop training and
demonstrations, internal and external publications and presentations
Some specifics
• Mechanical characterisation
• Process development
• Component application
• Environmental evaluation
Mechanical characterisation
Purpose: To establish the structural capability of selected lightweight materials/process
technologies against existing benchmarks
Selection
Demonstration
• Multiple materials - supplier engagement activities
• Standardised testing (tensile, flexure, lap shear)
• Candidate materials versus benchmark materials
• Testing demonstrator parts (flex, crush, fatigue, impact)
• FE model input and benchmarking
Simulation • Develop predictive FE model
CR
• Technology validation
• Benchmark performance against predictive models
Demonstrator beam FEA correlation
•
LS-DYNA, using developed MAT058 card, static flex
>
Indicates that modifications are required to model in key areas
Crush – comparison video
Process development – Rapid stamp forming
•
Material heated to target temperature
Process developed for top-hat demonstrator
(230°C, continuous heating process)
geometry and seat back part
>
Tool design analogous to sheet metal
forming process
>
Transferred to heated mould tool
(hand or shuttle, 10s, 100°C)
Med-high volume approach
•
Can use existing sheet metal
stamping infra-structure
Mould tool closes and stamp-forms part
(<10s)
•
Minimised cycle times (<90s)
•
Achieve 50k+ PPA on a single line
Part cools to de-mould temperature
(60s, ~120°C)
Process development - Joining technology
•
Principal aims:
>
Evaluate the state-of-the-art for joining processes
>
Investigate appropriate (production-relevant) joining methods for the candidate
materials selected in WS7
>
Provide timely input for demonstrator (top-hat/seat) testing
Adhesive bonding – curing and surface optimisation
• Study with Alpha Adhesives to optimise cure properties of
epoxy adhesive:
> Heat curing (e.g. BIW paint bake)
> Only just achieving cure with standard adhesive
> Alpha re-formulated 1K adhesive for lower cure
temp/time
• Improve bond strength +100% by optimising composite
substrate surface finish
> Peel fabric used in blank production
> Joint efficiency is doubled
Component application - Lightweight seating
•
Develop, manufacture and test an alternative lightweight seat
back structure
>
Candidate material is PA6-GF60, as for demonstrator beam
>
Selected candidate process is a modified press-forming
approach
>
•
Final design includes first stage optimisation steps
Overall target is 40% lighter than ‘Best in Class’
>
Benchmark frame is 2.9 kg
Light Weight Seating: Correlation example
Acceleration - FEA
70
60
X-Acceleration (g)
50
40
30
20
10
0
-10
0
0.02
0.04
0.06
Time (s)
0.08
0.1
Light Weight Seating: Thermoplastic Opportunity
Steel Assembly
Thermoplastic Concept
CF Thermoset
17kg
12kg
11kg
>200k p.a.
70k p.a.
500 p.a.
WS7 - LCA Approaches
•
Process optimisation (SPMJ)
>
Develop a lean but robust approach to environmental impact assessment at product
concept stage that is consistent with LCA and carbon foot printing methodologies
>
•
Validate proposals and roll out to project partners and other key stakeholders
Strategic direction (Ricardo):
>
Develop top down methodologies for estimating the life cycle CO2 emissions
associated with different powertrain architectures
>
Demonstrate a lean methodology to provide strategic direction to industry for
reducing environmental impact of complete vehicle or systems
•
Demonstrator component assessment (WMG): seat, top hat